105 Ammo Question

[MAJ_Fubar]

Noting that the CMC 105 round is tagged as US, does anyone know which round is it replicating? The M774 was our first DU round, but was a marginal performer compared to the older 735. The M833 proved quite capable against Iraqi T-72s and the listed muzzle velocity and penetration data seem to fit. If it's the M900 though, it's definitely underperforming. Long discussions with various Master Gunners left the impression the 900s could out penetrate the M829, though not by much.

[Ssnake]

I pulled that one straight from Jane's Ammunition Handbook 2009/10 ... because it was one of the rounds where the data provided allowed to make a ballistical and performance estimate (not always the case with the JAH).

According to it, this round was developed by Chamberlain Manufacturing Corporation (now a part of the General Dynamics corporate sprawl) as a private venture. It is no longer marketed, so I guess it was never sold in large quantities. But who knows. Maybe they sold off the manufacturing rights to someone else.

[MAJ_Fubar]

Cool, just wondering.

[Mogwa]

Isn't the CMC 105 just a M-900 with a tungsten penetrator instead of DU?This could be the reason it underperforms vs expected M-900 stats. Isn't penetrator material composition factored in now, according to the release notes?

Mog

[Ssnake]

Isn't the CMC 105 just a M-900 with a tungsten penetrator instead of DU?

I doubt this. The projectile assembly of the CMC105 is 5.8kg, that of the M900 is 6.86kg. The muzzle velocities are near-identical, but the M900 projectile is 711mm long while the CMC's penetrator length is 444.5mm (these two figures aren't directly comparable; the "projectile length" includes fin tail section and ballistic cap while the penetrator doesn't). Still, this is too much of a difference to be explained like this.

[Ssnake]

Isn't penetrator material composition factored in now, according to the release notes?

Yes, but don't overestimate the effect of it. dU gives the greatest benefit over tungsten at impact velocities of around 1200m/sec, and then it is about 10%. At 1800m/sec it's down to maybe 5% and beyond 2200m/sec there is no practical difference any longer.